My Source of Strength
by MoonfireHikari
Summary: A girl is found on Iroh's ship . She has no memories of how she got there, but she knows what she has to do. She finds herself stuck with the fire nation due to her admiration towards Iroh and for that same reason, she ends up following Zuko on his journey to restore his honor. Seeing how desperate he is, she thinks to herself, 'Why not help him…for now...' (ZukoxOC)
1. CHP 1: The Lost Girl

**Hello, everyone! Moonfire here with, finally, a fanfiction for Avatar: The Last Airbender!  
Don't get me wrong, I love Zuko and Mai together...but I love Zuko more~  
So I decided to create an OC for him who goes on his journey together.**

 **Do give it a read if it catches your eyes~ (Moonfire, 29/10/2018)**

* * *

Chapter 1: The Lost Girl

General Iroh was in his office, busy planning his strategies to the Earth Kingdom capital. He stopped when he suddenly heard commotions outside. Iroh exited his office. He heard a few of his soldiers talking.

"Who is this little girl?" a soldier asked.

"How did she get onboard our ship?" another one asked.

Iroh arrived at the main deck to check up on them. They seemed to be surrounding someone. The soldiers stood up straight when they saw him. They lined up to give him a better view of what they were observing. Iroh saw an eight-year-old girl in tattered clothes. She was in a battle stance, as if ready to strike anyone who threatens her. She was wearing an ear cuff. Iroh recognized the insignia.

"Father, what is going on?" Lu Ten, Iroh's only son came up to him.

He set his eyes on the girl, surprised to see one on a ship full of men. The girl calmed down a little when she saw Lu Ten. She seemed to be amazed by him. Lu Ten smiled, squatting down in front of her. He caught a glimpse of the ear cuff she was wearing.

"My, my, you have a fierce face…" he was amused.

"Hmph…" the girl replied.

"What is your name?" Lu Ten asked.

"Isla…" she replied short.

"She must be a fighter if she can sneak into our ship unseen," Lu Ten remarked.

Isla blinked at Lu Ten. The young man smiled at the girl.

"If you have taken a liking to her, then…let's bring her along…" Iroh said to his son.

Lu Ten nodded. He picked the girl up into his arms. The rest of the soldiers did not say anything. They respected Iroh's decision. Lu Ten gave Isla a room for her to rest. She got change into a Fire Nation dress. She stared at herself in the mirror. She glanced up at the ear cuff she was wearing.

"I will succeed my mission…" she muttered.

Lu Ten would train Isla some martial arts and firebending. Even though she could not bend at all, the young man never gave up on her. He just believed that she was a late bloomer. As time passed, Isla became one of the best warriors in martial arts. She spent most of her time with Lu Ten, training and discussing battle tactics. Lu Ten hardly let her participate in battle as she is a girl and he wanted her safe.

Soon, Isla joined Iroh and Lu Ten in making history, breaching the Outer Wall of Ba Sing Se. When Lu Ten lead the frontlines of the war, Isla stayed by Iroh's side. The inevitable happened; Lu Ten was killed before they could seize the Inner Wall. Isla comforted Iroh but it was not enough to lift his fighting spirit back up. He ended his siege.

After a long journey around the world, Iroh returned home with Isla as his adopted daughter.

* * *

It was the first time Isla has ever stepped into the Fire Nation, not to mention, the royal palace. She was given her own room next to Iroh's. He spent most of his time in his room or the studies. Isla did some exploring around the place, getting familiar with her surroundings. She caught sight of a girl about her age, throwing some bread crumbs at the ducklings in the pond.

"Hey! You shouldn't do that!" she shouted.

The girl stopped, glaring at Isla. "Who're you?"

Isla glared back at the girl. The girl raised a brow, recognizing her.

"You're uncle's adopted daughter. I bet you don't know who I am?" she smirked.

"Of course, I do! You're Princess Azula…and a princess should not be acting like that!" Isla replied.

"Hmmm… Whatever," Azula shrugged, walking away.

Isla was still glaring at her. Suddenly, Azula spun around and threw a fire shot at Isla. The girl sidestepped to dodge the attack. She turned to Azula who had a smirk on her face. Azula kept on attacking with more firebending. Isla swiftly avoided each one, even pushing away Azula's hand gracefully, as if she as dancing, not fighting. Azula aimed another strike using her palm, but Isla pushed it away with the back of her palm. Azula kicked with fire, Isla ducked to avoid it, elbowing Azula on her side, causing her to topple. There was a brief pause. Azula was getting impatient. Isla was still calm. They came at each other, Azula with firebending and Isla with a punch, but their respective hands were held off by someone.

"Enough, both of you!" Iroh said sternly.

Azula pulled away. She huffed before taking her leave. Iroh turned to his daughter with a stern look. Isla avoided his eyes, looking guilty.

"Care to explain what had happened?" he asked.

"She was picking on the ducklings…" Isla replied, feeling angry again.

"And what did you do? Pick a fight with her?" he asked.

She shook her head. "She started throwing fire at me, so I dodged away, like I promised you…and Lu Ten," she explained.

Iroh took a seat under the tree. "Good then. Come sit," he invited her.

Isla obliged, sitting beside him. He pulled out a bun from inside of his sleeve and started feeding on the ducklings and their mother. Isla joined.

"Listen to me, Isla. They must never know who you truly are," he reminded her.

"I know but my mission…" she muttered.

"I know of your mission and when the time comes, do what you must," Iroh said with a smile.

"Thank you, father…" Isla replied.

* * *

One fateful evening, thirteen-year-old Zuko was looking for his uncle. He passed by Isla's room and heard her humming a song. He took a peek through the curtains and saw her bending water, making it to swirl around her dagger. Shocked, he barged into her room. Isla lost her concentration, shifting her attention to the prince. She got out of bed, standing up straight.

"You're a waterbender?!" he exclaimed.

Isla averted his gaze. Zuko approached her with the urgency to ask more questions. She just froze at her spot, trying to stay calm.

"How did you deceive my uncle?" he asked. "Why are you even here?"

"It's confidential…but all I can say, I was found by father on his ship. I can't really recall how I ended up there," she explained, avoiding his eyes.

"Uncle helped you?" Zuko was even more shocked.

"I've been learning martial arts from Lu Ten. I shared my secrets with only him, but yes, your uncle helped me survive which is why I helped him breach Ba Sing Se…" she replied.

Both Zuko and Isla went quiet. They did not know what to say to each other. Isla glanced up at Zuko. She could see that his eyes show compassion and care, just like Iroh's.

' _I wonder if he ever noticed that about himself…'_ she thought.

Zuko took a glimpse of Isla who looked away immediately when their eyes met. He could see the fierce determination and the slight softness from her face.

"Since uncle accepted you, then I should too. I won't tell anyone," he gave in.

"Thank you so much, Prince Zuko," Isla smiled happily.

Zuko looked away from her and nodded. Iroh came in, froze when he saw Zuko with Isla. The young prince excused himself after taking one last glance at the girl.

"Did he…?" Iroh hesitated to ask.

"He found out I'm a waterbender, but for your sake, he promised not to tell…" she explained.

Iroh pulled her into a hug. "I am so glad to hear that! I thought I was going to lose another child…"

Isla returned the hug. "You're never going to lose me… I promise."

Iroh smiled. "I hope so."


	2. CHP 2: When It All Begin

**Hello, everyone! Thank you all for reading this. By the way, I actually like Iroh and his wisdom so much, which is why I make use of him in my story! Like, what a great uncle Zuko has and I am so jealous!**

 **Anyways, thank you for reading. I hoped you did enjoy this chapter, as much as I enjoy writing it. - (Moonfire, 4/11/2018)**

* * *

Chapter 2: When It All Begin

Ten-year-old Isla walked around the royal palace. She caught sight of Zuko training with Piandao, a swordmaster. The man stopped when he saw her. Isla bowed as a greeting. She walked up to them.

"I see you're teaching Prince Zuko the art of fighting…with dual broadswords?" she muttered.

Piandao nodded. "Well, yes. Prince Zuko seems to take a liking to them."

"May I join?" Isla asked.

"What can you do?" Zuko raised a brow in confusion.

Piandao handed Isla a sword. "Do not underestimate her, Prince Zuko."

Isla spun it around, getting into a stance. Her lips formed a smirk. Zuko readied himself. Piandao signaled them to begin. Isla charged in fast. Zuko was taken by surprised. He used both of his swords to parry when Isla brought her sword in front of him. Isla took a step back, swiping her sword at Zuko's legs. Zuko jumped to dodge it. Isla smiled at Zuko's reaction. She elbowed him in the stomach, sending him onto the ground with an 'ergh!'.

"You're fast…" Zuko remarked.

"I was trained by the best," Isla said proudly.

"Who's that?" the prince asked Piandao.

The swordmaster shook his head. "It was not me."

"Lu Ten," Isla spoke, handing the sword back to Piandao.

She was about to take her leave when Zuko called for her.

"Hey, come join again sometime. It would be fun to have a sparring partner than just learn the techniques," he said to her.

Smiling, Isla replied, "Sure."

From that one invitation, Isla started joining Zuko's sword lesson occasionally. They soon developed mutual respect towards each other. Zuko shared most of his troubles with Isla. She was pretty good at listening to him. He was comfortable around her. They became the closest of friends before that _incident_.

* * *

Isla's eyes darted around, checking her surroundings. Her right ear twitched at the sound of the bushes. She jumped away from a fire shot. She water-whipped her opponent.

"Eouch!" Iroh shouted.

He came out of the bushes, clapping his hands. Isla bowed to him and then, smiled.

"That was nice, though I can't use much of my bending…" she said.

Iroh nodded. "They mustn't know…" he reminded her.

Isla nodded. She caught sight of Zuko passing by. Iroh turned towards what she was looking at. A soldier approached them. They shifted their gaze to him. The soldier saluted Iroh.

"General Iroh, you are summoned by Fire Lord Ozai…for the meeting…" he said.

Iroh nodded. Isla smiled and nodded to her father. He patted her head before leaving. Isla started training alone, doing some moves Lu Ten had taught her. She was having fun. After a couple of hours of training, Isla made her way to the war chamber. She waited outside for her father, assuming that the meeting was already over.

"Hey, you," Azula's voice was heard.

Isla turned to the young princess. "Yes?" she replied.

"Prepare to be entertained," the princess said.

Isla was confused. Azula gestured the girl to follow her and she did. Isla looked around. In the middle of the large room was some sort of stage. Two people stood there from each end of it. She realized that they were inside the arena. She wondered what was happening.

"Isla? How did you get inside?" Iroh asked.

"Father? …Princess Azula invited me. What is going on?" Isla replied.

"It's an Agni Kai," Azula cut them off.

Iroh shook his head. "Just watch and you will understand…" he said to his daughter.

The girl nodded. She sat beside her father to watch. Zuko stood up and spun around to face his opponent. His opponent did the same. The whole room gasped to see who was on stage with Zuko. Isla widened her eyes in surprised.

"He could never fight the Fire Lord…" she muttered to herself.

Zuko instantly fell to his knees while his father stepped closer to him.

"Please, father. I only had the Fire Nation's best interests at heart. I'm sorry I spoke out of turn!" he begged.

Ozai did not stop. "You will fight for your honor," he said sternly.

"I meant you no disrespect. I am your loyal son!" Zuko continued to plead.

"Rise and fight, Prince Zuko!" Ozai shouted.

"I won't fight you." Zuko said, trembling.

"You will learn respect and suffering will be your teacher!" the Fire Lord continued.

Isla averted her eyes from the inevitable. Zuko's scream echoed in the room.

"You refused to fight. I will not tolerate such cowardice," the Fire Lord said.

Zuko was still suffering from the burn, but he sat there and listened.

"You are banished from this kingdom and you will not return until you capture the Avatar!" the Fire Lord continued.

He took his leave and left Zuko there to let him process what he had declared. People started leaving a few minutes after Fire Lord Ozai left. Iroh tapped Isla's shoulder and gestured her to leave with him. She shook her head, turning to look at Zuko who was still frozen on the stage.

"I'll go get him…" she muttered.

Iroh nodded, walking towards the exit. Isla made her way to the stage. She stood behind Zuko. He was staring at the floor, still in shock. The girl looked around to make sure they were alone. She knelt beside him.

"Let me look at the wound…" she said.

She took out the water from the small tube she had around her arm. She touched his face. Zuko didn't react at first, but then he pushed her hand away. He stood up, facing his back towards her.

"I need to get going," he muttered.

"Zuko, let me help," Isla insisted.

"No!" he replied coldly.

Isla was taken aback by his shout. She heaved a sigh. She stood up.

"I'm sure father will be more of a help than me," she said.

She passed by him and exited the room. Iroh was waiting for her. He smiled when he saw her. She replied with a smile too. She made her way to her room to get herself ready. When she was about to get out, Iroh came in. He saw her with her small sack.

"You're coming?" he asked.

She nodded. "If you're going, then I am too. I don't want to stay here without you."

Iroh gave in. "Very well. Let us take our leave."

Zuko was on the ship Isla and Iroh were boarding. The girl stopped when she saw him. Their eyes met for mere seconds before they both turned away from each other. Iroh smiled, amused at Zuko and Isla. Before going to her cabin, Isla made her way over to Zuko.

"I'm sorry," she spoke up.

"For what exactly?" Zuko asked.

Shrugging, she replied, "Nothing in particular, just sorry…"

* * *

Zuko was in his cabin on the ship, meditating. Isla came by. She stood at the entrance. Zuko opened his right eye and took a glance at her. The girl rolled her eyes.

She asked, "Would you like me to check on your injuries? Those bandits sure did you one…"

"I'm fine. They deserve the beating," Zuko replied.

Giggling, she said, "You're the one who got beaten."

She entered the room while bending water around her hand. She insisted to check on his injuries. Zuko reluctantly took off his uniform. Isla started off with two deep cuts on his right arm.

"They're just scratches," Zuko insisted.

"As long as you have me, these 'scratches' won't be a problem," Isla replied.

"It was never a problem," he mumbled.

"Yeah, right…" she scoffed, whispering, "Thanks for saving me…"

Zuko rolled his eyes at the girl. Half an hour later, Iroh was on his way to check up on them. He stopped when he heard the two tongue-fighting with each other.

"Oh no…" he muttered to himself.

"It wasn't supposed to hurt anymore! You're lying!" Isla shouted.

"It still does! You're not that skilled, huh?!" Zuko shouted back.

"Why you…!" Isla growled.

What Iroh heard next was probably a chair thrown off to the wall or a bed broken into half. He rushed to Zuko's room to see what was happening. When he got there, Zuko was lying on the floor flat on his stomach. Isla had her right foot on his back, claiming her victory.

"What are you doing?" Iroh brought himself to ask.

"He was being a bad patient," Isla replied.

"I wasn't…! Uncle, get this girl off of me…" Zuko drawled weakly.

Iroh shook his head. Isla took her foot off of his back. She huffed at Zuko before leaving him with her father.

"Make sure you drink the herbal tea I made you!" she shouted from outside.

"She's a monster!" Zuko exclaimed.

Iroh chuckled. "She is attached to you. Isla is usually reluctant to heal anyone," he explained.

"She healed everyone just fine," the prince remarked.

Iroh shook his head. "Not as thorough and precise as your injuries."

Zuko huffed. "As if! She just likes torturing me in return!"

Iroh laughed out loud this time. He made his way out of the prince's room, still laughing. He was indeed entertained by Zuko and Isla's behavior towards each other.


	3. CHP 3: Steamed Fish

Chapter 3: Steamed Fish

Zuko looked around the deserted area. Isla poked her head here and there, excited to see something else after so long.

"There is nothing here anymore!" Zuko complained.

"The Western Air Temple has long been deserted after our men's attack centuries ago," Iroh explained.

"I was hoping to find clues on the Avatar," Zuko huffed angrily.

Isla played with a few droplets of water she could find, happily humming a tune. Zuko looked angrily at her. She stared blankly at him in return, indifferent of how angry he was. Iroh shook his head at her behavior.

"Oh, would you just calm down. This is our first stop after the incident with the bandits we encountered," she said to him.

"It was no incident, you started the fight!" Zuko reminded her.

"They were trying to rob someone!" Isla shouted.

"It was none of our business. We shouldn't have stopped to help," he shouted back.

Isla growled angrily. Iroh held her right shoulder. She turned to him. He shook his head. Zuko started looking around, hoping that he could find even the smallest hint that the Avatar was still alive. Isla heaved a sigh.

"Since we're already here, why not camp here for the night? Take some time to heal and a good rest…" Iroh suggested.

Isla nodded as an agreement. "I can help you with your meditation," she said to Zuko.

"No! Rests are for lazy people. We must get going. There's nothing here!" Zuko said.

Isla water-slapped him. She was annoyed with his impatience.

"Take a break or I'll break your bones one by one," she half growled.

"You're not the boss of me! We're heading out, NOW." Zuko said sternly.

Isla puffed her cheeks angrily. Iroh held her shoulder again to make sure she calmed down. They both watched as Zuko exited the Western Air Temple to head back on the road. Isla flashed a smile at her father as a sign she was okay. Iroh nodded in return. She ran to catch up with Zuko. Zuko ignored the girl as she started to play with water droplets again.

* * *

Eleven-year-old Isla was resting in her cabin, cleaning her dagger. She was humming the same tune she always hummed. Iroh came in after knocking. She looked at her father.

"Are you okay?" he asked.

"I'm fine," Isla replied casually.

"I heard Prince Zuko yelled at you again," he started.

The girl stopped what she was doing. She sighed. "It was nothing. It's just his pent up anger."

Iroh raised a brow. "Are you sure, my dear?" he asked.

Isla nodded. "Yeah. I'd rather he yells at me than at your royal soldiers," she said.

"I see you care for him," Iroh remarked.

"I guess. It's just so much fun teasing him and making him angry," she chuckled.

Iroh shook his head. "That is not how a girl should act," he said to her.

Isla nodded. "I know, but it's the only way I should act around him. I don't want to get too attached…"

"Isla…about your mission, can you wait until Zuko captures the Avatar? I want him to be able to find his own path. I want _you_ to be able to find your own path too," Iroh explained.

Heaving a sigh, she replied, "Sure. There's no rush…but, it has been a year already."

Iroh nodded to her. He patted her head and smiled. Isla put away her dagger.

"By the way…we need to head to the nearest port soon. We're running out of food," she said.

"I will inform Prince Zuko," her father said.

"No, I'll do it," Isla insisted.

Iroh obliged without questions. She made her way to Zuko's cabin. The fourteen-year-old prince was busy staring at his map at the time. Before she could knock, Zuko had already guessed it was her.

"What do you need?" he asked.

"We're running out of food supplies. Can we stop at the nearest port to replenish?" she asked.

Zuko huffed. "Fine. Inform the captain."

"Okay~" Isla chirped.

She glanced at Zuko who was sneezing. She looked concern.

* * *

Isla was the first to get down the ship when it docked. They were in a small port town in the Earth Kingdom territory. Zuko refused to even get out of his room. Iroh followed his daughter around to remind her that she should not be poking her nose too much.

"We need some decent food," Isla said.

"What do you plan to make?" Iroh asked curiously.

Isla stopped to think. "Hmmm, we can eat steamed fish tonight. The weather's a bit cold. Something warm is nice. Then…" she kept on talking.

Iroh watched as she made her way to a vegetables stall. She started to pick some. The man walked over to her.

"Do we still have enough money to go around?" he asked, concerned.

Nodding, the girl replied, "Yes, we do. I've sold some wood sculptures at the village where we met the bandits. The money is enough before the new season comes in."

Iroh nodded to her. He followed her to the next stall where she picked out ducks and chickens. Their last stall was to look for fish and spices. Once they were done, Iroh boarded the ship with the ingredients. Isla took her time around the port town to get some fresh air.

"Where is she, Uncle?" Zuko asked, impatient.

"She is getting some fresh air," Iroh replied casually.

"We need to get going!" he shouted angrily and then, sneezed.

He stomped his way off the ship to fetch her. A soldier came up to Iroh with a concerned look.

"Is it okay to let him go, Sir?" he asked.

"Don't worry. My daughter knows how to handle him," Iroh said, chuckling.

Isla was busy looking at some ornaments when Zuko came up to him. She frowned when she saw how unhappy he was. He stopped in front of her. She fixed her posture to face him.

"What?" she asked.

"We don't have time for this. Let's go!" Zuko huffed.

She sighed. "Why don't you take some time to appreciate the nature a bit?"

"I said we don't have time for -" the boy growled.

The girl interrupted, "Sure we do."

Zuko watched as she took a necklace and traded it with her ear cuff. The gem on the ear cuff was turned into a locket with the help from the blacksmith, the owner of the stall. She thanked him, paid the remaining fee and left. Zuko matched her pace.

"Why change to a necklace?" he asked.

"Well, you're acting all curious now…" Isla replied.

"I thought that was the only thing your family left you with," he remarked.

She sighed. "Yes, but I have father now. I don't need that…" she lied.

They boarded the ship and were on their way again. Isla rushed to the kitchen to inform the cook of what to cook. She helped him prepare the ingredients. Zuko didn't join them for dinner. Iroh volunteered to send him some afterwards. When Iroh entered his cabin, Zuko was on his bed, staring at the ceiling.

"You should eat. Isla's cooking is rare," he informed.

"I'll eat that soon…" Zuko replied and then, sneezed.

"You're catching a cold," Iroh said as a matter-of-fact.

"I'm fine," the prince replied.

"Come sit. Have dinner. You might feel better…" the man insisted.

Zuko groaned. He sat down opposite of his Uncle, staring at his dinner. It was just like Isla had said before, steamed fish. He started to have some. It was warm and refreshing.

"This is pretty good," he muttered.

Iroh nodded. "I guess Isla knew that you have a cold, so she decided on this menu."

"Why?" he asked in a soft voice.

"Because she cares about you is the reason," Iroh replied.

Zuko stared at his food and continued to eat. A few hours later, he went over to Isla's cabin. She was meditating, water swirled around her as she did. She could sense that he was watching. She sent the water back into the large pot in the corner of her cabin.

"Do you need something?" she asked.

"Do you have time?" he asked.

He held in an incoming sneeze. Isla smiled at him. She gestured him to take a seat in front of her. He faced his back to her. Isla started her massage on his shoulder.

"As tensed as always…" she muttered.

"Well, yeah. You're getting on my nerves," he replied.

"Want me to break your bone?" she asked, half growling.

Zuko shook his head. "No."

Isla took out some water. She untied his hair, started using her healing power around his head to sooth him. He let out a sigh.

"Thanks for the steamed fish. It was good…" he whispered.

"You're welcome," she smiled.


End file.
